Rudbeckia plant named ‘RUDHT55’

ABSTRACT

A new and distinct cultivar of Rudbeckia plant named ‘RUDHT55’, characterized by its compact, upright to outwardly spreading and mounded plant habit; freely branching growth habit; freely flowering habit; single-type inflorescences with grayed orange and greyed purple to brown bi-colored ray florets positioned above the foliar plane on strong peduncles; and good garden and container performance.

Botanical designation: Rudbeckia hirta.

Cultivar denomination: ‘RUDHT55’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Rudbeckia plant, botanically known as Rudbeckia hirta, commonly referred to as Black-eyed Susan, and hereinafter referred to by the name ‘RUDHT55’.

The new Rudbeckia plant is a product of a planned breeding program conducted by the Inventor in Zuidwolde, The Netherlands. The objective of the breeding program is to create new compact Rudbeckia plants with numerous attractive inflorescences.

The new Rudbeckia plant originated from a cross-pollination made by the Inventor in Zuidwolde, The Netherlands in July, 2015 of two unnamed proprietary seedling selections of Rudbeckia hirta, not patented. The new Rudbeckia plant was discovered and selected by the Inventor as a single flowering plant from within the progeny of the stated cross-pollination in a controlled environment in Zuidwolde, The Netherlands in July, 2016.

Asexual reproduction of the new Rudbeckia by in vitro meristem culture in a controlled greenhouse environment in Zuidwolde, The Netherlands since March, 2017 has shown that the unique features of this new Rudbeckia are stable and reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

Plants of the new Rudbeckia have not been observed under all possible combinations of environmental conditions and cultural practices. The phenotype may vary somewhat with variations in environmental conditions such as temperature and light intensity, without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined to be the unique characteristics of ‘RUDHT55’. These characteristics in combination distinguish ‘RUDHT55’ as a new and distinct Rudbeckia plant:

-   -   1. Compact, upright to outwardly spreading and mounded plant         habit.     -   2. Freely branching growth habit.     -   3. Freely flowering habit.     -   4. Single-type inflorescences with grayed orange and greyed         purple to brown bi-colored ray florets positioned above the         foliar plane on strong peduncles.     -   5. Good garden and container performance.

Plants of the new Rudbeckia differ from plants of the parent selections in the following characteristics in plant habit as plants of the new Rudbeckia are more compact and uniform than plants of the parent selections.

Plants of the new Rudbeckia can be compared to Rudbeckia hirta X Echinacea purpurea ‘ET-RDB 02’, disclosed in U.S. Plant Pat. No. 25,243. Plants of the new Rudbeckia differ primarily from plants of ‘ET-RDB 02’ in the following characteristics:

-   -   1. Leaves of plants of the new Rudbeckia are more serrated than         leaves of plants of ‘ET-RDB 02’.     -   2. Plants of the new Rudbeckia and ‘ET-RDB 02’ differ in ray         floret color as plants of ‘ET-RDB 02’ have yellow, orange and         reddish-colored ray florets.     -   3. Ray florets of plants of the new Rudbeckia are slightly         upright whereas ray florets of plants of ‘ET-RDB 02’ are         horizontal in aspect.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying photographs illustrate the overall appearance of the new Rudbeckia showing the colors as true as it is reasonably possible to obtain in colored reproductions of this type. Colors in the photographs may differ slightly from the color values cited in the detailed botanical description which accurately describe the colors of the new Rudbeckia.

The photograph on the first sheet comprises a side perspective view of a typical flowering plant of ‘RUDHT55’ grown in a container.

The photograph at the top of the second sheet is a close-up view of a typical flowering plant of ‘RUDHT55’.

The photograph at the bottom of the second sheet is a close-up view of typical leaves of ‘RUDHT55’.

DETAILED BOTANICAL DESCRIPTION

The aforementioned photographs and following observations, measurements and values describe plants grown in 19-cm containers during the late summer and early autumn in an outdoor nursery in Zuidwolde, The Netherlands and under cultural conditions typical of commercial Rudbeckia production. During the production of the plants, day temperatures ranged from 18° C. to 30° C. and night temperatures ranged from 6° C. to 18° C. Plants were 18 weeks old when the photographs were taken and 17 weeks old when the detailed description was taken. In the following description, color references are made to The Royal Horticultural Society Colour Chart, 2015 Edition, except where general terms of ordinary dictionary significance are used.

-   Botanical classification: Rudbeckia hirta ‘RUDHT55’. -   Parentage:     -   -   Female, or seed, parent.—Unnamed proprietary seedling             selection of Rudbeckia hirta, not patented.         -   Male, or pollen, parent.—Unnamed proprietary seedling             selection of Rudbeckia hirta, not patented. -   Propagation:     -   -   Type.—By in vitro meristem culture.         -   Time to initiate roots.—About ten days at soil temperatures             about 15° C. and ambient temperatures about 20° C.         -   Time to produce a rooted young plants.—About 30 to 35 days             at soil temperatures about 15° C. and ambient temperatures             about 20° C.         -   Root description.—Medium in thickness; fleshy; typically             white in color, actual color of the roots is dependent on             substrate composition, water quality, fertilizers, substrate             temperature and physiological age of roots.         -   Rooting habit.—Freely branching; medium density. -   Plant description:     -   -   Plant and growth habit.—Herbaceous perennial; compact,             upright to outwardly spreading and mounded plant habit;             strong and freely branching growth habit with about ten             primary lateral branches each with about three secondary             lateral branches; dense and bushy appearance; moderately             vigorous growth habit; medium growth rate.         -   Plant height.—About 33.8 cm.         -   Plant width.—About 45.3 cm.         -   Lateral branches.—Length: About 13.6 cm. Diameter: About             5 mm. Internode length: About 2.6 cm. Angle: Primary lateral             branches are upright to about 45° from vertical and             secondary lateral branches are about 30° from primary             lateral branches axis. Strength: Moderately strong. Texture             and luster: Densely pubescent; moderately glossy. Lenticels:             Length: About 0.2 mm. Width: About 0.1 mm. Color: Close to             N186C. Color: Developing branches, close to 144A to 144B;             developed branches, close to 144A with axillary stripes,             close to 143A, and at the nodes, close to 187B. -   Leaf description:     -   -   Arrangement.—Alternate, simple; sessile.         -   Length.—About 18.4 cm.         -   Width.—About 5.7 cm.         -   Shape.—Narrowly obovate to narrowly elliptic.         -   Apex.—Acute.         -   Base.—Long attenuate to cuneate.         -   Margin.—Serrate.         -   Texture and luster, upper and lower surfaces.—Pubescent,             rough; matte.         -   Venation pattern.—Pinnate.         -   Color.—Developing leaves, upper surface: Close to between             137B and 143A. Developing leaves, lower surface: Close to             143A. Fully expanded leaves, upper surface: Darker than             between 137B and 143A; venation, close to 148C. Fully             expanded leaves, lower surface: Close to 146B; venation,             close to 146C. -   Inflorescence description:     -   -   Type and arrangement.—Single-type inflorescence form with             elliptic-shaped ray florets and tubular disc florets;             inflorescences borne on terminal and axillary peduncles             above and beyond the foliar plane on strong peduncles; ray             and disc florets arranged acropetally on a capitulum.         -   Fragrance.—None detected.         -   Flowering season.—Plants begin flowering about 100 days             after planting; long flowering period, plants flower             continuously during the late summer to late autumn in The             Netherlands.         -   Inflorescence longevity.—Good postproduction longevity with             inflorescences lasting about two to five weeks on the plant;             inflorescences not persistent.         -   Quantity of inflorescences.—Freely flowering habit,             typically about 30 developing and fully developed             inflorescences at one time.         -   Inflorescence buds.—Height: About 2.4 cm. Diameter: About             2.5 cm. Shape: Broadly ovate. Texture and luster: Densely             pubescent; matte. Color: Close to 151D and 172B.         -   Inflorescences.—Diameter: About 9.7 cm. Depth (height):             About 2.7 cm. Diameter of disc: About 2.7 cm. Receptacle             height: About 1.2 cm. Receptacle diameter: About 9 mm.             Receptacle shape: Deltoid. Receptacle color: Close to 157C             to 157D.         -   Ray florets.—Quantity and arrangement: About 20 per             inflorescence arranged in a single whorl. Length: About             4.5 cm. Width: About 1.4 cm. Shape: Elliptic. Apex:             Emarginate. Base: Cuneate. Margin: Entire. Aspect: When             developing, upright and when fully opened, perpendicular to             slightly upright to peduncle axis. Texture and luster, upper             surface: Smooth, glabrous; velvety; matte. Texture and             luster, lower surface: Smooth, glabrous; slightly velvety;             matte. Color: When opening, upper surface: Distally, close             to N163C to N163D; proximally, darker than between N186C and             200A. When opening, lower surface: Close to 151C, 151D and             172A. Fully opened, upper surface: Distally, close to 169A;             proximally, darker than between N186C and 200A. Fully             opened, lower surface: Close to 163A, 163V, 166B and 166C.         -   Disc florets.—Quantity and arrangement: About 700 per             inflorescence arranged in a spiral of about 15 whorls.             Length: About 8.5 mm. Width: About 4 mm. Shape: Lower 85%             fused and tubular, elongated. Apex: Acute. Aspect: Upright.             Texture and luster: Smooth, glabrous; glossy. Color, when             opening and fully opened, inner and outer surfaces:             Distally, close to between N186C and 200A; proximally, close             to 155A.         -   Phyllaries.—Quantity and arrangement: About 30 per             inflorescence arranged in about two whorls. Length: About             3.3 cm. Width: About 4 mm. Shape: Narrowly oblong. Apex:             Bluntly acute. Base: Broadly cuneate. Margin: Entire.             Texture and luster, upper and lower surfaces: Densely             pubescent; matte. Color, upper surface: Slightly darker than             143A. Color, lower surface: Close to 143A to 143B.         -   Peduncles.—Length: About 10.8 cm. Diameter: About 4.5 mm.             Strength: Strong. Aspect: Mostly upright. Texture and             luster: Densely pubescent; moderately glossy. Color: Close             to 144A with axillary stripes, close to 143A.         -   Reproductive organs.—Androecium (present only on disc             florets): Quantity per disc floret: About five. Filament             length: About 4 mm. Filament color: Close to 155A. Anther             shape: Narrowly oblong. Anther length: About 3.5 mm. Anther             width: About 0.5 mm. Anther color: Close to 200A. Pollen             amount: Scarce. Pollen color: Close to 17B. Gynoecium             (present only on disc florets): Pistil length: About 6 mm.             Style length: About 4.5 mm. Style color: Close to 155A.             Stigma diameter: About 4 mm. Stigma shape: Cleft, decurrent.             Stigma color: Close to between 200A and 202A. Ovary color:             Close to NN155B.         -   Seeds and fruits.—Seed and fruit production has not been             observed on plants of the new Rudbeckia to date. -   Disease & pest resistance: Plants of the new Rudbeckia have not been     observed to be resistant to pathogens and pests common to Rudbeckia     plants. -   Garden performance: Plants of the new Rudbeckia have been observed     to have good garden performance and to tolerate wind, rain, high     temperatures about 35° C. and to be suitable for USDA Hardiness     Zones 5 to 10. 

It is claimed:
 1. A new and distinct Rudbeckia plant named ‘RUDHT55’ as illustrated and described. 